Let's work with mud. I've made 3 mixes of Dark Earth and European Earth to get different tonalities. On the lower hull, I applied them quickly and fixed them with some Pigment Fixer. It takes time to dry, so I'll be able to work on it later on.

For the front hull and the sides of the Jagdtiger, I first made some Earth Effects, Dark Mud and Fresh Mud spatters. Then, I applied differents pigments that I worked again using the same products. I always start with the brightest tones and I progressively darken the surface.